Combination Therapy With Rituximab and Cyclophosphamide for Remission Induction in ANCA Vasculitis

Introduction Remission induction in antineutrophil cytoplasmic autoantibody (ANCA) vasculitis may be complicated by slow response to treatment and toxicity from glucocorticoids. We describe outcomes with a novel remission induction regimen combining rituximab with a short course of low-dose, oral cyclophosphamide and an accelerated prednisone taper. Methods Patients were included in this retrospective study if they had newly diagnosed or relapsing ANCA vasculitis with a Birmingham Vasculitis Activity Score for Wegener Granulomatosis (BVAS-WG) ≥3 and received a standardized remission induction regimen. The primary outcome was complete remission, defined as a BVAS-WG of 0 and a prednisone dose of ≤7.5 mg/d. Results We identified 129 patients who met the inclusion criteria, 31% of whom also received plasma exchange (PLEX) for rapidly progressive glomerulonephritis (RPGN) or diffuse alveolar hemorrhage. Seventy percent of patients had myeloperoxidase (MPO)-ANCA and 9% had relapsing disease. Median time to complete remission was 4 months (interquartile range [IQR] 3.9–4.4), and by 5 months 84% of patients were in complete remission. Prednisone was tapered to discontinuation as tolerated, such that the median prednisone dose at 8 months was 0 mg/d (IQR 0–2.5). In patients with RPGN, proteinase 3–ANCA was associated with a greater increase in eGFR at 6 months compared with MPO-ANCA (16 vs. 5.6 ml/min per 1.73m2; P = 0.028). During the year following remission, 1 major relapse occurred over 122 patient-years. Serious infections occurred more frequently in patients receiving PLEX and were associated with increasing age and diffuse alveolar hemorrhage. Four deaths occurred, 3 of which were associated with serious infections. Conclusion Combination therapy was efficacious, allowed for rapid tapering of high-dose glucocorticoids and was well tolerated.